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Abstract:

A desiccant air conditioner has a high energy efficiency due to the
absence of excessive heat loss due to ventilation. In order to meet this
requirement, the desiccant air conditioner is equipped with a honeycomb
rotor wash-coated with agents having capabilities of absorptions of
humidity, carbon dioxide and nitrogen, and this honeycomb rotor is
divided into at least an absorption zone and a desorption zone. The air
in a room is, after being passed through the absorption zone, fed back to
the room, and the air which is passed through the desorption zone is
exhausted into outside of the room. In this way, carbon dioxide and
nitrogen in a room, the latter quantity being corresponded to that of the
consumed oxygen in the room, are exhausted into outside of the room,
allowing to exhaust carbon dioxide and at the same time to keep the
oxygen density to within an allowed limit without the need of excessive
ventilation.

Claims:

1. The desiccant air conditioner, which is equipped with a honeycomb
rotor having the capabilities of both at least humidity and carbon
dioxide absorption or absorbing process together with the nitrogen
absorption capability, wherein the honeycomb rotor is divided into at
least an absorption zone and a desorption zone, air in a room is, after
being passed through the absorption zone, fed back to the room, and air
which is passed through the desorption zone is exhausted into outside of
the room.

2. The desiccant air conditioner, which is equipped with a honeycomb
rotor having the capability of at least humidity absorption or absorbing
process together with a honeycomb rotor having the capability of carbon
dioxide absorption or absorbing process and the nitrogen absorption
capability, wherein both honeycomb rotors are divided into at least
absorption zones and desorption zones, the air in a room is, after being
passed through the respective absorption zones, fed back to the room, and
the air which is passed through the respective desorption zones is
exhausted into outside of the room.

3. The desiccant air conditioner according to claim 1, wherein a purge
zone is provided, and the air in the room is, after being passed through
the purge zone, heated and passed through the desorption zone, then
exhausted into outside of the room.

Description:

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is based upon and claims the benefit of priority
from Japanese Patent Application No. 2010-124240 filed on May 31, 2011,
the entire contents of which are incorporated herein by reference.

BACKGROUND

[0002] This invention is concerned with a desiccant air conditioner, where
humidity-absorbing agents such as silica-gel or zeolite are used, and
provides a system which could improve air-quality in a room without the
necessity of ventilation.

[0003] The desiccant air conditioner employs humidity-absorbing agents to
provide dry air, thereby yielding air with very low dew point compared
with a conventional dehumidifier by refrigeration process. In addition,
the desorption process in the humidity-absorbing agents can be carried
out using exhaust gas from an internal combustion engine, for example,
thus yielding high potential of energy saving.

[0004] To add to this, high-humidity gas is produced in the process of dry
gas production, and the former can be supplied to a room to add humidity
there.

[0005] This type of the decicant air conditioner is not only being
employed for air conditioning of buildings, but its possible application
to air-conditioner for hybrid cars is now actively pursued. In the latter
case, hybrid cars have high overall energy efficiency, implying the
amount of heat available from exhaust gas to be insufficient for
defrosting windscreens. As techniques for the latter case, the patent
documents 1 and 2 have been disclosed.

[0006][Patent document 1] JP 2000-280724

[0007][Patent document 2] JP 2001-47844

[0008][Patent document 3] JP 2009-52753

[0009] In the patent document 1, room air in a car is circulated so as to
reduce heat loss due to ventilation and at the same time to secure fresh
air which is supplied only to avoid excessive CO2 accumulation in
the car.

[0010] However, the process described in the patent document 1 still
requires ventilation, thereby yielding a problem of energy loss.

[0011] Further, the patent document 2 describes an air conditioner for a
car, where dehumidifying efficiency be improved by energy saving. For
example, the section 0003 describes a problem caused by ventilation. In
order to cope with this, the section 0004 describes a reduction of the
amount of ventilation air.

[0012] However, some ventilation is necessary, and the problem of energy
loss due to this ventilation cannot be overcome.

[0013] Further, the process disclosed in the patent document 3 utilizes a
honeycomb rotor to absorb poisonous gas and carbon dioxide in a room and
then to exhaust them to outside. This process exhausts only these gases,
and thus has much higher energy efficiency compared with that trying to
reduce room densities of these gases by ventilation.

[0014] However, the process disclosed in the patent document 3 has a
problem of gradually reducing oxygen density in the room for an extended
period of use. The present invention tries to avoid energy loss by
ventilation, but still keep the room air clean enough by employing the
desiccant air conditioner.

SUMMARY

[0015] In order to overcome the above-mentioned problems, this invention
introduces a honeycomb rotor with at least wash-coated humidifying and
CO2 absorbing agents, with this rotor having at least two zones with
one for absorption and the other for desorption, and the absorption zone
is circulated with room air and the air degassed during the desorption
zone is exhausted to outside.

[0016] The air-conditioner based on this invention is composed as
described above such that carbon dioxide produced by human is absorbed in
the honeycomb rotor and exhausted during the passage of the desorption
zone. In this process, oxygen in the room is consumed, but nitrogen is
also absorb/desorbed by wash-coating nitrogen absorbing agents into the
rotor, thus keeping the oxygen density in the room. Incidentally,
atmospheric compositions are about 78% nitrogen, about 21% oxygen and
about 1% others, thus the oxygen composition is kept at around 21% if we
could make the system exhausting the ratio of carbon dioxide 1/nitrogen 4
so that nitrogen is exhausted, the amount of which exactly corresponds to
the consumed oxygen in the atmospheric composition in the room.

[0017] On the other hand, the allowable upper limit of carbon dioxide is
regulated as 0.1% by the Building Standards of Japan (0.5% by the
national occupational health and safety laboratory of the United States
and American Conference of Governmental Industrial Hygienists (ACGIH).
Because the amount of carbon dioxide in a room directly affects human
health, it is usually thought to be necessary to have ventilation of 30
m3/h for an individual person in the room. However, if carbon
dioxide and nitrogen, the latter amount being corresponded to the amount
of consumed oxygen, can be exhausted from the room, it is possible to
keep both the densities of carbon dioxide and oxygen in the room without
the necessity of ventilation of 30 m3/h.

[0018] For example, the amount of carbon dioxide exhaust per person is
0.02 m3/H, then combining with an exhaust of nitrogen of 0.08
m3/H, one needs to ventilate the amount of 0.1 m3/H. This is
only 1/300 of the amount of ventilation required to meet the allowable
carbon dioxide density, decided by the Building Standards.

[0019] In addition, the desiccant air conditioner based on the present
invention has a wash-coated honeycomb rotor, so that dehumidification of
a room can also be carried out simultaneously.

[0020] Additionally, the honeycomb rotor can be wash-coated with absorbing
agents of volatile organic compounds (VOCs hereafter), so that VOCs can
also be diminished from the room, thus enabling to improve the air
quality further.

[0021] Particularly in recent years, opto-chemically induced smog have
been reported to appear very frequently in large city areas, and it is
feared to take in these smog into a room if one ventilate room air. In
addition, exhaust gases from automobiles along busy roads and odorous
smells exited from kitchens in central urban areas might also be taken
into the room by ventilation. However, if the desiccant air-conditioner
is employed, the air in the room can be purified without the necessity of
ventilation, thus eliminating the above-mentioned problems.

[0022] The invention described in claim 1 can be carried out by installing
a honeycomb rotor which is wash-coated with agents having at least
humidity absorbing capability or absorption process and/or carbon dioxide
absorbing capability or absorption process, and the rotor is divided into
at least absorbing and desorbing sections, thereby the air passing
through the absorbing section being fed back into the room again while
the air passing through the desorption section being exhausted to outside
of the room. In this way, some fractions of carbon dioxide and nitrogen
are exhausted into outside, while keeping the densities of carbon dioxide
and oxygen within respective allowable limits.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] These and other objects and advantages of the present invention
will become more apparent and more readily appreciated from the following
description of the preferred embodiments, taken in conjunction with the
accompanying drawings of which:

[0024] FIG. 1 shows the air flow of the first embodiment of the invention.

[0025]FIG. 2 shows the air flow of second embodiment of the invention.

[0027] Reference will now be made in detail to the preferred embodiments
of the present invention, examples of which are illustrated in the
accompanying drawings, wherein like reference numerals refer to like
elements throughout.

[0028] In the following, examples of practical applications of the
decicant air conditioner based on the present invention are described in
detail using the attached figure. The number 1 in the figure shows a
honeycomb rotor, which is shaped into a rotor using non-flammable sheets
such as ceramic fiber papers being corrugated (wave-like structured), and
the rotor is wash-coated with inorganic humidity absorbing agents such as
silica-gel and hydrophilic zeolite or with polymeric humidity absorbing
agents such as ion exchange resin and polymeric adsorbent material or
with other humidity absorbing agents such as lithium chloride.

[0029] In addition, the honeycomb rotor is wash-coated with calcium
carbonate, sodium carbonate, tri-ethanol amine, mono-ethanol amine,
hydrotalcite and ion exchange resin. The zeolite families of CaA, NaX,
CaX, LiLSX and NaLSX also absorb carbon dioxide, but preferentially
absorb humidity, thus stopping of absorbing carbon dioxide any further.
Therefore, a honeycomb rotor using these latter agents may be wash-coated
in the exit side of the rotor, or may be built up as a separate rotor and
made a unit by combining with other type of rotor.

[0030] To add to this, the zeolite families of CaA, NaX, CaX, LiLSX and
NaLSX also absorb nitrogen, thus rotors using these agents can absorb
nitrogen as well as carbon dioxide. However, as stated above, these
agents preferentially absorb humidity and then stop absorbing other
substance any further.

[0031] A hopeful configuration is to wash-coat the inlet portion of the
rotor with weakly basic ion exchange resin, which absorb both humidity
and carbon dioxide, and the exit portion with the zeolite families of
CaA, NaX, CaX, LiLSX and NaLSX, so that the ion exchange resin at the
inlet portion absorb both humidity and carbon dioxide and then zeolites
more preferentially wash-coated at the exit portion mainly absorb carbon
dioxide and nitrogen gases. By employing this configuration, zeolites can
most effectively absorb both nitrogen and carbon dioxide gases, without
excessive effects of humidity.

[0032] In addition, one may wash-coat the honeycomb rotor 1 with active
carbon or hydrophobic zeolite. In this way, the honeycomb rotor has a
capability of absorbing odorous smells and VOCs as well.

[0033] The honeycomb rotor 1 is divided into a desorption zone 2, a purge
zone 3, and an absorption zone 4. Both the purge zone 3 and the
absorption zone 4 are supplied with room air using a blower (the blower
is conventional, so that it is not shown in the figure).

[0034] The air in the room 7 is, after passing through the absorption zone
4 of the honeycomb rotor 1, subdivided into a channel leading to the
purge zone 3 and that for the supply route to the room 7.

[0035] The air, after passing through the purge zone 3, is heated using a
heater 5, then passes through the desorption zone 2 and is exhausted into
outside of the room. The air, after passing through the absorption zone
4, is supplied to the room 7, where a cooling system 6 such as an
evaporator or a cooling coil may be employed in between in case of
excessive temperature rise.

[0036] The desiccant air conditioner based on the present invention is
constituted as described above, and its operation is described in the
following.

[0037] First, we consider a case when one needs to make a room air drier,
such as to avoid moist formation in winter or to dry washed clothes in a
room. In such circumstances, while the honeycomb rotor 1 is being
rotated, the room air is passed through the absorption zone 4 and the
purge zone 3. The air is dried while passing through the absorption zone
4 and some fractions of carbon dioxide and nitrogen are removed, and the
air is fed back to the room. At the same time, the heater 5 is switched
on, and the heated air passes through the desorption zone 2 and desorbs
the absorbed humidity and carbon dioxide there, then being exhausted into
outside of the room.

[0038] In this way, the room air is dried and some fractions of carbon
dioxide and nitrogen in the room are exhausted into outside of the room.
In addition, the temperature of the air after passing through the
absorption zone 4 is raised by the absorption heat, thus yielding the
effect of heating for air-conditioning.

[0039] When one needs to dehumidify air in a room in a rainy season, the
room air is heated by passing through the absorption zone 4, but the
heated air is cooled by the cooling system 6, thus reaching the room as a
cool air.

[0040] Because the air passing through the cooling system 6 is dry, the
latent load in the cooling system 6 (the load caused by the dew formation
of humidity in the air) does not exist. Therefore, the capacity of the
cooling system 6 can be small. If a heat pump is employed where the
cooling system 6 works as an evaporator and the heater 5 as a radiator,
the overall energy consumption can be made small.

[0041] There are cases when VOCs are exhausted into a room, such as a new
furniture is brought into the room or wall papers are replaced. In such
cases, the VOCs in the room are absorbed in the honeycomb rotor 1, and
desorbed in the desorption zone 2, thus being brought out to outside of
the room.

[0042] As explained above, it is possible to exhaust some fractions of
carbon dioxide/nitrogen and VOCs without the necessity of ventilation,
thus avoiding the energy loss associated with it. Also, the case when
outside air contains harmful substances, it does not cause any problem
because of the ventilation being not involved in the process. In such a
case, even when outside air tries to get into the room, it may be
captured in the honeycomb rotor 1, thus keeping the room air clean.

[0043] Also, an air cleaner is employed in order to keep the air in the
room 7 clean in case the outside air is dirty or polluted. In such a
case, if there are many people in the room 7 who breathe and exhaust
carbon dioxide, the latter is exhausted using the air conditioner based
on the present invention, thus keeping the oxygen density to within the
allowable limit. In addition, the amount of air which is brought into the
room 7 is the same amount of that of carbon dioxide and nitrogen being
exhausted using the honeycomb rotor, and it is of small quantity so that
an air cleaner can easily purify it.

[0044]FIG. 2 shows the flow diagram of the second application of the
present invention. In the above example of the first application, the
room air was made to pass through the purge zone 3. In contrast, the
outside air is made to pass through the purge zone 3 in this second
application. In this second application, the amount of air reduced from
the room is only those of carbon dioxide and nitrogen being absorbed in
the honeycomb rotor 1 and exhausted to outside of the room.

[0045] For this reason, the amount of ventilated air for the second
application is even smaller than that for the first one. This second
application is most suitable for the case when the outside air is
polluted and/or dirty.

[0046] In the case of air conditioning for a car, it is hopeful to carry
out the air heating and ventilation at the same time, so as to avoid the
moisture formation. However, much energy of heating is lost by the
process of ventilation. Also, the moisture avoidance in rainy season and
air conditioning for cooling/humidity reducing conditions in summer also
require ventilation to lower the density of carbon dioxide in the room,
thus losing much energy for cooling.

[0047] If this invention is applied to air conditioning for a car, it is
possible to carry out the air conditioning and dehumidification of the
cabin room while carbon dioxide and some portions of nitrogen, the latter
quantity being corresponded to the consumed oxygen, are exhausted, thus
allowing the densities of carbon dioxide and oxygen in the cabin to be
kept to within the respective allowable limits. In this way, the amount
of air necessary to take into the cabin can be made small, just to
compensate the amount exhausted through the honeycomb rotor by the
absorption/desorption processes, thus enabling to carry out the heating
and cooling requirements without much energy loss while at the same time
to carry out the carbon dioxide reduction and maintenance of oxygen
density.

[0048] In a case of a gasoline-powered car, much exhaust heat is produced
and no special equipment is required for air heating. However, in a case
of an electric car, a large amount of exhaust energy does not exist,
necessitating saving of this required energy for air heating. For the
latter case, it is necessary to reduce the amount of ventilating air, so
that heated air is not allowed to exit excessively. The present invention
provides much energy saving due to minimum ventilation.

[0049]FIG. 3 shows the flow diagram for the third application 3. In both
the above first application 1 and second application 2, the honeycomb
rotor 1 had a purge zone 3. In contrast, the purge zone 3 is not equipped
in the third application 3, and the outside air is guided into the
desorption zone 2. In this third application 3, similarly as for the
second application 2, the amount of reduced room air is due to carbon
dioxide and nitrogen absorbed in the honeycomb rotor 1 and desorbed in
the desorption zone 2.

[0050] In the third application 3, the heater 5 and the cooling system 6
can also be functioned by a heat pump and a radiator, allowing to reduce
the energy consumption.

[0051] In all three applications above, the ratio of exhausted carbon
dioxide and nitrogen can be controlled by the temperature of the heater
5. In other words, because the desorption temperatures for both carbon
dioxide and nitrogen are different, the adjustment of the temperature of
the heater facilitates the control of desorbed amounts of these two
gases.

[0052] This invention is concerned with the desiccant air conditioner,
where carbon dioxide and some portions of nitrogen, the latter quantity
being corresponded to the consumed oxygen, are exhausted, thus allowing
the densities of carbon dioxide and oxygen in the room to be kept within
the respective allowable limits. In this way, the invention provides a
basis for the decicant air conditioner which significantly reduces the
energy loss associated with ventilation.

[0053] The invention has been described in detail with particular
reference to preferred embodiments thereof and examples, but it will be
understood that variations and modifications can be effected within the
spirit and scope of the invention covered by the claims which may include
the phrase "at least one of A, B and C" as an alternative expression that
means one or more of A, B and C may be used, contrary to the holding in
Superguide v. DIRECTV, 69 USPQ2d 1865 (Fed. Cir. 2004).

Patent applications by Hiroshi Okano, Fukuoka JP

Patent applications by SEIBU GIKEN CO., LTD.

Patent applications in class ATMOSPHERE AND SORBENT CONTACTING TYPE

Patent applications in all subclasses ATMOSPHERE AND SORBENT CONTACTING TYPE